This invention relates to apparatus for repairing a pipeline and method for using same.
One method of repairing damaged sewer pipe is to excavate the area surrounding the sewer pipe and replace the broken portion. This is a very expensive and labor intensive solution and is also an inconvenience to residents living in the area and utilizing roadways overlying the area.
Another solution is in situ relining of sewer pipes. In situ methods typically utilize a resin coated liner which is inserted into the existing sewer pipeline and unrolled against the sewer pipe. The unrolled liner is held against the existing sewer pipe while the resin cures to form a new pipe lining within the existing pipe.
One example of such a method is shown in U.S. Pat. No. 4,366,012 dated Dec. 28, 1982. In this patent is shown a process utilizing an elongated outer tube having an inner tube comprised of felt. Uncured resin is introduced into the tube and is used to impregnate the felt inner tube. The two concentric tubes are then inverted into the end of the sewer pipe to be repaired and the inversion process continues until the area of the sewer pipe needing repair has been reached by the inverting tubes. Upon inversion the impregnated felt liner is placed on the outside of the original outer liner, and is pressed against the interior surface of the sewer pipe. When the resin cures a new pipe liner is provided at the area to be repaired.
U.S. Pat. No. 4,366,012 shows a method for impregnating the inner felt tube with uncured resin. The impregnation is initiated by pouring the uncured resin in one end of the two concentric tubes. A slit is made in the outer tube approximately 12 inches from the other end of the outer tube. A vacuum cup is placed over the slit and a vacuum is drawn from the outer tube, thereby causing flattening of the outer tube and assisting the resin to spread through the fabric liner and impregnate it from one end to the other. Once the resin has impregnated the entire felt liner the vacuum is shut off and a patch is solvent welded over the slit.
There are several disadvantages to this impregnation process. The slit makes the outer tube or bladder weaker. Furthermore the cutting of a slit and the patching of a slit are time consuming. If the removal of the vacuum source from the vacuum cup is not timed properly, the vacuum cup will suck up some of the resin, thereby rendering the vacuum equipment inoperable.
Another disadvantage of the method of repairing a sewer pipe shown in U.S. Pat. No. 4,366,012 is that the outer bladder and the inner felt tube must be inverted into the sewer pipe beginning at a manhole located nearest to the area to be repaired. The inverted tubes must then extend to the area to be repaired, thereby requiring a length of tube which will reach from the nearest manhole to the area to be repaired.
For example, if a 300 foot long liner is required, the method of U.S. Pat. No. 4,366,012 requires pouring resin at one end of the tube, moving down the tube for approximately 50 feet, making a slit in the coating of the fabric liner, placing a suction cup over the slit, drawing the resin to that point, removing the vacuum, and placing a patch over the slit. Then it will be necessary to move another 50 feet down the tube and repeat the process. This process will continue at approximately 50 foot intervals until the desired location on the tube is reached.
The foregoing 50 foot intervals are necessary because it is only possible to draw a vacuum so far down the tube and still be effective.
Another disadvantage of the method shown in U.S. Pat. No. 4,366,012 is that the fabric liner is coated. In some applications, it would be desirable to utilize a liner that is not coated and instead use a liner that is separate from the bladder.
Most of the sewer mainlines are usually located in roadways and are buried at a considerable depth. These mainlines have lateral pipes that branch off to houses, businesses and industries. Lateral lines are conduits for carrying waste from these houses, businesses and industries out to the mainline sewer.
Mainline sewers are typically straight with access manholes at spaced apart positions along the length of the main sewer line. Mainline sewers are usually owned by municipalities or utility companies who utilize the services of civil or professional engineers for the design of sewer installations, inspections, and final work acceptances.
Lateral sewers on the other hand are typically installed by local plumbers or home owners. It is common to find numerous bends or fittings in a lateral sewer as well as inappropriate materials used in the original construction. These lateral installations offer a greater challenge in repair than do the reconstruction of the straight and professionally designed mainline sewers.
Therefore, a primary object of the present invention is the provision of an improved apparatus for repairing a pipeline and method for using same.
It is another object of the present invention to provide an apparatus for the insertion and installation of a new liner into an existing pipe which is particularly suitable for the spot repair of damaged sections of a given pipeline, wherein the liner is introduced into the existing pipe by means of a carrier which encloses the liner and protects it from contact with the surrounding pipe walls until the liner is in its desired location within the existing pipe.
It is a further object of the present invention to provide a method for relining pipes in which the pipe liner is secured to an inflation bladder, impregnated with resin and encapsulated within a positioning element, the positioning element then being inserted into an existing pipe and fluid being introduced under pressure into the positioning element to cause the inflation bladder and the liner secured thereto to invert outwardly from within the positioning element to a placement position near the compromised pipe section, the inflation bladder expanding radially in response to fluid pressure and urging the liner into contact against the pipe wall, and subsequently removing the inflation bladder and positioning the element from the pipe.
A further object of the present invention is the provision of an improved method for impregnating a resin absorbent material with an uncured resin while the resin absorbent material is within an inflatable bladder tube.
A further object of the present invention is the provision of an improved method for repairing lateral sewer pipe and particularly for repairing the juncture between the lateral sewer pipe and the mainline sewer pipe.
A further object of the present invention is the provision of an improved carrier which is integral with the bladder tube, and which permits the positioning of the bladder tube within the sewer pipeline in the general area of the pipeline to be needing repair.
A further object of the present invention is the provision of a method for repairing sewer pipeline wherein the outer carrier is disposable after use.
A further object of the present invention is the provision of an improved method and apparatus for repairing pipeline which is economical in manufacture, durable in use, and efficient in operation.